emerging infectious disease

emerging and re-emerging disease

basically, anything we’re worried about

• new mutations
• change in environment
• resistant strains
• species jumps (encounter and compatibility: changes via recombination, mutation)

Do we need to understand everything?

• reservoir ecology
• pathogen biology
• human-reservoir interactions

How do we understand? How do we predict?

Batrachochytrium dendrobatidis

Reminders

• fungal pathogen
  • most other chytrids are saprophytes, plant pathogens
  • B. salamandrivorans: salamander pathogen (more restricted)
• first discoved in poison dart frogs
• caused die-offs in E Australia, Central America, Colorado, California …
• association with high altitude?
• occurred in pristine areas (probably not anthropogenic?)
• pathogenesis via screwed-up osmoregulation

Very confusing …

• some species decline in the absence of Bd
• some species stable in the presence of Bd
  (Bd may have been there all along?)
• susceptibility:
  • ability to bask
  • antimicrobial peptides

tipping point hypothesis: in populations all the time, but something happened to increase virulence/reduce tolerance or resistance

• climate change/El Niño ?

• ultraviolet radiation?

• cooler temperatures? (basking etc.)

• pesticides?

• combination (species × temperature × U/V × pesticide × …)

• Pounds et al. (2006): “chytrid-thermal-optimum hypothesis”

• Rohr et al. (2008): “numerous other variables, including regional banana and beer production, were better predictors of these extinctions”

• Rohr & Raffel (2010)

novel pathogen hypothesis: mutation/speciation + dispersal

• “Out of Africa” hypothesis
• earlier/broader detection in historical specimens: CA/bullfrog, Brazil …
• genomics (challenging!)
• Asian sampling

monkeypox

climate change

• warming
  • ‘good’ or ‘bad’ for pathogens?
  • vector biology
    • extended range
    • higher activity?
• changes in seasonality, hydrological cycles
• local landscape change
  • hydrology
  • land cover (Lyme disease)
  • forest cover
• changes in reservoir communities

dilution effect (Keesing & Ostfeld, 2021)

• does increased biodiversity decrease disease?
• variation in reservoir competence
• high-quality hosts decrease with increasing biodiversity
  • encounter reduction; host regulation; vector preferences

Kain & Bolker (2019)

Rohr et al. (2020)

prediction

Pulliam & Dushoff (2009)

Walker et al. (2018)

Han et al. (2020)

References

Han, B. A., O’Regan, S. M., Paul Schmidt, J., & Drake, J. M. (2020). Integrating data mining and transmission theory in the ecology of infectious diseases. Ecology Letters, 23(8), 1178–1188. https://doi.org/10.1111/ele.13520

Kain, M. P., & Bolker, B. M. (2019). Predicting West Nile virus transmission in North American bird communities using phylogenetic mixed effects models and eBird citizen science data. Parasites & Vectors, 12(1), 395. https://doi.org/10.1186/s13071-019-3656-8

Keesing, F., & Ostfeld, R. S. (2021). Dilution effects in disease ecology. Ecology Letters, 24(11), 2490–2505. https://doi.org/10.1111/ele.13875

Pounds, A. J., Bustamante, M. R., Coloma, L. A., Consuegra, J. A., Fogden, M. P. L., Foster, P. N., La Marca, E., Masters, K. L., Merino-Viteri, A., Puschendorf, R., Ron, S. R., Sánchez-Azofeifa, G. A., Still, C. J., & Young, B. E. (2006). Widespread amphibian extinctions from epidemic disease driven by global warming. Nature, 439(7073), 161–167. https://doi.org/10.1038/nature04246

Pulliam, J. R. C., & Dushoff, J. (2009). Ability to Replicate in the Cytoplasm Predicts Zoonotic Transmission of Livestock Viruses. The Journal of Infectious Diseases, 199(4), 565–568. https://doi.org/10.1086/596510

Rohr, J. R., Civitello, D. J., Halliday, F. W., Hudson, P. J., Lafferty, K. D., Wood, C. L., & Mordecai, E. A. (2020). Towards common ground in the biodiversity–disease debate. Nature Ecology & Evolution, 4(1), 24–33. https://doi.org/10.1038/s41559-019-1060-6

Rohr, J. R., & Raffel, T. R. (2010). Linking global climate and temperature variability to widespread amphibian declines putatively caused by disease. Proceedings of the National Academy of Sciences, 107(18), 8269–8274. https://doi.org/10.1073/pnas.0912883107

Rohr, J. R., Raffel, T. R., Romansic, J. M., McCallum, H., & Hudson, P. J. (2008). Evaluating the links between climate, disease spread, and amphibian declines. Proceedings of the National Academy of Sciences, 105(45), 17436–17441. https://doi.org/10.1073/pnas.0806368105

Walker, J. W., Han, B. A., Ott, I. M., & Drake, J. M. (2018). Transmissibility of emerging viral zoonoses. PLOS ONE, 13(11), e0206926. https://doi.org/10.1371/journal.pone.0206926

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Last updated: 2022-04-06 10:44:24